The present invention relates to firearms in general, and more particularly to a removable and replaceable linear bearing insert for the ways between the slide of an automatic firearm, such as a pistol for example and the frame or receiver of the firearm.
In most automatic or semi-automatic firearms, such as automatic pistols for example, the frame or receiver is provided at its top edge with a groove disposed on each side and in which is engaged the inwardly directed tongue or flange of the slide. Reciprocation of the slide, either manually or under the recoil action of a round of ammunition being fired, accomplishes the functions of extracting a spent cartridge through an ejection port, and returning the hammer to the cocked position. The return of the slide under the action of a return spring causes feeding of a fresh cartridge from the magazine or clip into the chamber and causes the bolt to close the chamber, in readiness to fire a subsequent round of ammunition upon depressing the trigger.
The reciprocating motion of the slide relative to the receiver must be smooth, and without binding that may cause jamming. The ways defined between the receiver grooves and the slide tongues or flanges in mutual sliding surface engagement must provide an assembly permitting a smooth reciprocation of the slide, but without undue play that may cause the slide, and consequently the barrel disposed in a longitudinal bore within the slide, to oscillate sideways or in elevation relative to the receiver, in the course of the slide reciprocating motion. Although reciprocation of the slide may be achieved accurately along the longitudinal axis of the receiver ways when the firearm is relatively new, even though manufacturing tolerances and poor match of components may at first result in a slight play within acceptable limits between the slide and the receiver, through wear of the linear bearing surfaces in mutual engagement resulting from repeated firing of the firearm the original tolerances gradually widen, with resulting increased play in the sliding fit between the slide and the receiver. Such increased play is annoying to a sharpshooter, distracting and conducive to reduced accuracy in target practice, more particularly in competition.
In spite of all the loving care given to their favorite firearms by sharpshooters, especially competition marksmen, firearms eventually are entrusted to a skilled gunsmith for modification, for customizing, for repair and for overhaul, including tightening of the slide relative to the receiver. Such tightening of the slide is commonly effected by placing the slide in a vise and slightly bending the slide sidewalls beyond the module of elasticity of the metal such as to narrow the space between the slide tongue inner edges, with the result that the slide tongues engage the receiver grooves with decreased lateral play. If too much pressure is applied by the vise during tightening of the slide, the metal may fracture, thus requiring costly replacement of the slide. Metal may also be welded onto the slide grooves and tongues, and onto the receiver grooves and tongues, and the receiver and the slide are re-grooved with precision such as to provide a more accurate match of the bearing surfaces and a compromise between tight fit and smooth action of the slide.
The present invention provides accurate, smooth and reliable fitting between the slide of a firearm, such as a pistol, and the receiver without causing any mechanical stress to be applied to the slide, without welding, without machining the slide and receiver bearing surfaces, and without modifying the metallurgy or composition of metal and without stressing the metal as results from welding a coating of metal on the bearing surfaces.